The Next Generation Network (NGN) adopts a distributed network structure. It bears voice, video and multimedia services effectively, and is implemented such that the service application, service control, and service transmission are separated from each other. An NGN in the prior art includes an MG and a Media Gateway Controller (MGC). The MGC is configured to manage call states and control bearer resources of the MG; and the MG is configured to create, modify, release and manage media streams under control of the MGC.
Generally, the MG works in Back-to-Back (B2B) mode when it serves as a border gateway. That is, a termination is created in either of two Internet Protocol (IP) networks, and is allocated an address of the IP network of the termination. This address acts as a source address for sending media streams and a destination address for receiving the media streams in the respective IP networks of terminations. Generally, each media stream has a definite peer for each termination, and the filter rule is intended only for the address of this peer. Therefore, there is only one filter rule usually.
The MG in the H.248.64 protocol works in routing mode, and uses a termination to represent an interface. That is, a termination corresponds to an interface rather than an address in an IP network. The corresponding filter rule is set on the termination that represents the interface. However, a single filter rule is not enough as a firewall packet filter rule on the interface. There may be tens of thousands of firewall packet filter rules on an interface.
In the prior art, the MGC is unable to control the filter rules on the interfaces of the MG effectively, namely, the MGC is generally unable to perform control operations such as an audit for the filter rules in the properties of the terminations of the MG.